Dynamoelectric machine

ABSTRACT

A dynamoelectric machine stator has a primary winding for single phase alternating current input and a secondary winding for polyphase alternating current to be supplied from output terminals. The secondary winding is connected such that at least two frequencies are provided at the terminals. The rotor has two windings thereon for excitation, one being excitable for one frequency output and the other rotor winding being excitable for another frequency output at the secondary terminals. Another secondary winding may be provided on the stator to obtain a desired output terminal voltage at one of the selected frequencies.

United States Patent 1 1 a 1111 3,930,175 Chirgwin 1 1' Dec. 30, 1975 [5DYNAMOELECTRIC MACHINE I 3,378,756 4/1968 Potter 321/64 X Inventor:Keith M. Chirgwin, Palos Verdes FOREIGN PATENTS OR APPLICATIONS Estates,953,913 4/1964 United Kingdom 310/185 [73] Assignee: The GarrettCorporation, Los I Angeles, Calif: Primary Exammer-J. D. MillerAssistant Examiner-Robert J. Hickey Flled? p 10, 1973 Attorney, Agent,or FirmBen E. Lofstedt; Frederick 2 App! No: 39 043 G. Michaud, Jr.;Albert J. Miller 57 ABSTRACT [52] US. Cl. 310/; 310/179; 310/185; 1

321/63, 322/63, 322/90, 318/147 A dynamoelectr c machme stator has a prmary wmd- [51] m C12 6 5/32 ing for single phase alternating currentinput and a [581 11,11 0'1 315121'3131111'516/156199 185 secondarywinding for polyphase. alternating 3l0/l89 322/62 86 to be supplied fromoutput terminals. The secondary 5 1 9 winding is connected such that atleast two frequencies are provided at the terminals. The rotor has two[56] References Cited windings thereon for excitation, one beingexcitable 1 for one frequency output and the other rotor winding UNITEDSTATES PATENTS being excitable for another frequency output at the2,041,875 5/1936 Stone! .l 310/ UX secondary terminals, Anothersecondary winding may 231571926 5/1939 Suns 322/62 X be provided on thestator to obtain a desired output Q terminal voltage at one of theselected frequencies. 3:197:66O 7/1965 Leischner 310 160 18 Claims, 3Drawing Figures Sheet 1 0f 3 Dec. 30, 1975 US. Patent U.S. PatentDec.30,1975 Sheet20f3 3,930,175

I I j llll l i|||l|l|l11l Fig.2.

Sheet 3 of 3 3,930,175

Dec. 30, 1975 U8. Patent DYNAMOELECTRIC MACHINE BACKGROUND OF THEINVENTION The transmission and transfer of alternating currentelectrical power from the generating source to the end user requiresparticular consideration of many variables when the source is stationaryand the user is in motion, as in the case of an electrical railway. Oneof the principal factors to be considered is that of money outlay,either as a first cost or for the rehabilitation and updating ofexisting trackage and railway cars or vehicles. With the usual number ofvehicles per mile of track, the cost of electrification of the track ismany times the cost of the electrical equipment of the vehicle, and itthus behooves the designer to point efforts to a vehicle system in whichthe cost of track electrification is minimized. It is recognized thathighest possible voltage, single phase power with reasonably high powerfactor, results in lowest track costs.

Insofar as voltage is a factor, it is desirable for the wayside powerdistribution system to furnish alternating current power at 25,000 oreven 50,000 volts in the case of station stop distances of the order of50 miles, for example. With voltages of this level, it is no longerpractical to furnish polyphase power through the pickup, and it becomesessential to utilize a third rail or overhead catenary system andpantograph pickup with current return in the grounded reaction rail tosupply single phase power. Given this situation of power supply from thetrack electrification it is seen that the equipment on board the vehiclemust be adapted to convert the high voltage single phase alternatingcurrent into power at the wheels and, at the same time, present areasonable power factor window for the source to look into. It isapparent, of course, that such on board equipment ought not exact anyundue penalty of weight and envelope.

The voltage aforesaid is too high for the traction motor or motors, so atransformer is needed aboard the vehicle. Furthermore, if the tractionmotors are of the induction type (either rotary or linear), polyphasepower is required at least at starting. On the other hand, either rotaryor linear induction motors present a poor power factor.

To meet this problem there was devised the Kando System used on theHungarian State Railways for a period extending from 1932 to sometimeduring the l950s. This system was featured by a free-running, rotatingsynchronous machine having a direct current excited rotor and a statorprovided with single phase power input and polyphase power outputwindings. This converting machine provided step-down transformer action,phase conversion, and power factor correction in a single entity, whoseweight was not of paramount importance since it was used on locomotives.For example, a typical Kando System, including the necessary auxiliaryaccessory equipment such as oil and water coolers and pumps, water tank,air circulating fans, and the like, occupied an envelope volume of about4,500 cubic feet and weighed over 13 tons.

Modern high speed transportation methods, utilizing either rotary orlinear types of polyphase induction motors, are not adapted to suchunwieldy, cumbersome and massive converting machinery exemplified by theKando System. Hence, later technology has tended to look in otherdirections for solutions to the problem of providing either trackedwheelor tracked-air-cushion transportation vehicles or magnetic levitationvehicles adapted to speeds upwardly to 300 to 400 miles per hour.

SUMMARY OF THE INVENTION The present invention is directed generally tomeans and methodsof transformation of alternating current electricalenergy from one characteristic form into another. There is provideddynamoelectric apparatus for converting alternating current from onevoltage to another with phase conversion coupled with power factorcorrection where the load tends to reflect an undesirable lagging orleading power factor back to the PP y- 2 Further provided is apparatusas aforesaid having dynamoelectric winding coils together withconnections coupled to a plurality of terminals, some of saidconnections establishing apparatus having one number of magnetic polesof said windings and other of said connections establishing apparatushaving another number of poles of said windings.

The apparatus may employ two sets of windings, one of which establishesa certain number of poles for said apparatus and the other establishes adifferent number of poles, at least a portion of said windings beingcommon to the other for the number of poles established thereby.

Specifically, the dynamoelectric apparatus may have a winding of alesser number of poles, e.g., two poles or four poles, and a winding ofa greater number of poles, e.g., six poles or ten poles, a portion ofthe six or ten pole winding being common to the respective two or fourpole winding. The number of volts per Hertz of current may besubstantially equal in both the windmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic illustrationof one form of the invention, together with an example of a system inwhich it would find use;

FIG. 2 is a winding layout and a connection scheme for providingdifferent numbers of magnetic poles in one form of the invention; and

FIG. 3 is a schematic diagram of one phase of a secondary windingincorporating the winding of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there isillustrated diagrammatically a dynamoelectric machine 10 functioning asa free-running synchronous converter, and having a rotor 12 adapted torotate within a stator provided with a single phase primary winding 14and a pair of polyphase secondary windings 16 and 18. Polyphase winding16 is comprised of wye connected phase windings 16-A, l6-B and 16-C;polyphase winding 18 is comprised of wye connected phase windings l8-A,l8-B and l8-C. Windings l6-A, 16-B and 16-C have a common connectionpoint 17; windings 18-A, l8-B and l8-C are common at point 19. The rotor12 has excitation windings 20 and 22, and may also be provided with adamper or amortisseur winding 24 if required for initial starting of themachine 10.

Single phase alternating current is supplied to the high voltage side ofthe primary winding 14 from an overhead catenary system 26 through apantograph 28, in the case of a system disposed on a railway transitcar,in which case the low voltage side of the winding I4 is coupled toreturn ground track through the wheels of the car. Direct currentexcitation of the windings 20 and 22 is furnished by a generator 30coupled to the windings via conductors 31 and a control apparatus 32which is adapted by means of a manual control level 33 to variablycontrol the current in the windings 20 and 22 as more particularlydescribed hereinafter. As will be appreciated, the exciter generator 30may be driven by the converter machine 10 if desired, as well knownpractice in the art.

As will be appreciated by those skilled in the art, the combination ofthe stator winding 14 with the rotor 10 and its excitation winding 20,for example, represents a known synchronous motor. This combination,together with a polyphase stator winding such as winding 16, isrepresentative of a synchronous converter adapted to convert singlephase current in the winding 14 at a high voltage, for example, into alower voltage polyphase current in the winding 16. As is known, thewinding 16 may supply an inductive load such as an induction motorhaving a relatively poor lagging power factor, with the machine 10providing corrective action to present a high power factor window. tothe single phase supply.

If the excitation winding 20 is of the 4-pole type, coupled with a4-pole connection of the primary winding 14, then the synchronous speedof the machine 10 will be 1800 rpm if the alternating current supply is60 Hz. Likewise, the secondary output winding 16 will be 4-pole toprovide 60 Hz polyphase current to the load. Within certain limits, thevoltage at the output of winding 16 may be varied by regulating thecurrent in the excitation winding 20. l

The additional excitation winding 22 and secondary winding 18 provide adiscrete step frequency change at the output of the winding 18. If, forexample, it is desired to provide selective output frequencies of 60 Hzand 150 Hz, then the winding 16 will provide the 60 Hz current asdescribed hereinabove. To obtain the 150 Hz frequency output, a l-polearrangement is indicated where the input frequency is 60 Hz. Thus theexcitation winding 22, as well as the output winding 18, are both woundand connected as Ill-pole arrangements. Furthermore, within reasonablelimits the output voltage of the winding 18 may be varied by regulatingthe current in the excitation winding 22.

It will be apparent to those skilled in the art that excitation of the4-pole winding 20 must be maintained at the required excitation level inorder to maintain the synchronous speed of the machine at 1800 rpm,otherwise the machine mightget out of step. Thus, when the winding 22 isenergized, the rotor 12 is excited with both. 4 and l0-polemagnetization and the output of the l0-pole stator winding 18 is 300 Hz.It would be totally unexpected by those skilled in the art that both 4and 10-pole excitation could be employed in one rotor with a 10-polestator winding having an output frequency 2% times that of the inputfrequency.

The output of the windings l6 and 18 is fed through a switchingapparatus 34 to the load, schematically shown as an induction motor 36.Preferably, the switching apparatus is under the supervision of thecontrol 32 by means of a relay coil 38, for example, which may beselectively energized to activate the switch means 34 for selectiveoutput of winding 16 or winding 18 to the load 36. It will beappreciated that the load 36 could be a rotary or linear inductionmotor. The invention herein is particularly efficacious in the 4 case ofa linear induction motor as utilized in a high speed transit railwaycar, since such a motor presents a very poor power factor to itssupply-because of the large air gap between the stator teeth and thereaction rail. The converter described provides the desired power factorcorrection.

The embodiment of the machine 10 of FIG. 1 effects a controlledtransfer, in substantially the following fashion, of alternating currentfrom the single-phase wayside or catenary system 26 to the loadrepresented as a polyphase induction motor 36. The rotor 12 of machine10 is first brought up to near synchronous speed from a standstill inknown fashion. This may be accomplished by energizing the primary statorwinding 14 and a phase-displaced starting winding (not shown) to providea rotating field for reaction by the damper winding 24 on the rotor.Thus, if the primary winding 14 and the starting winding are connectedas 4-pole windings, the synchronous speed will be 1800 rpm. It isobvious that the excitation winding 20 will also be a 4-polearrangement. Therefore, when the rotor 12 has accelerated to nearsynchronous speed the winding 20 is energized to a basic excitationvalue and the starting winding disconnected, at which time the machine10 acquires function in characteristic synchronous motor fashion. Itwill be apparent to those skilled in the art that the starting functionthus described briefly may be accomplished automatically by the control32 or manually by manipulation of the control lever 33, for example.

After the machine 10 is in step, the control lever 33 may be actuated tooperate the switch apparatus 34 so as to couple the secondary generatingwinding l6to the load and thereby energize the motor 36 with 3-phase 60Hz power having a relatively lower basic voltage value. Thereafter thelever 33 may be advanced to increase the excitation of winding 20 andthus increase the voltage output of winding 16 to the maximum designvalue. The increase of excitation with concurrent voltage increase ofwinding 16 results in acceleration of the load motor in stepless fashionfrom its start-up fro standstill to its running speed under load.

Further advance of the lever 33 thereafter effects an energization ofthe 10-pole excitation winding 22 to its basic excitation value and aconcurrent decrease of energization of the 4-pole excitation winding 20to a value sufficient to maintain the machine 10 in step at its constantsynchronous speed. This causes a nominal voltage at Hz to be generatedin the l0-pole secondary winding 18, and at this point in time theswitch apparatus 34 effects a disconnect of the load motor 36 from thewinding 16 and a connect with the winding 18. Thereafter the load motor36 is accelerated by the increased applied frequency, followed byacceleration resulting from stepless increase of voltage effected byincreasing excitation of winding 22 causedby further advance of thelever 33.

It will be understood, of course, that complex interacting effects maybe experienced between the windings 14, 18, 20 and 22 during the 150 Hzpower output to the load motor 36, hence varying energization of theexcitation winding 20 may be desirable to maintain the machine in step.

It was also conceived that portions at least, of the two secondarygenerating windings could be combined with a subsequent saving of copperand winding labor. P16. 2 is illustrative of such a combination effectedin .the case of a 60-slot stator, thus having 20 coils per phase (onlyone phase winding being shown, it being apparent that in such a caseeach of the other two phase windings would be identical but displacedand 40 slots, respectively, from that shown). As thus shown the winding40 for phase A, for example, has a coil span of slots 1-17 which thusprovides a pitch of on 10 poles and I4/l5 on 4 poles.

The winding 40 closes on itself. That is, it constitutes a closed loopwith no coil turn ends brought out for external connections. To this endthere are four principal winding group connectors 42, 44, 46 and 48 andsix supplementary winding group connectors 30, 52, 54, 56, 58 and 60.Connectors 42, 44, 46 and 48 are coupled to terminals 62, 64, 66 and 68,respectively for connection to the external circuit, as explained indetail hereinafter.

The coil grouping and winding arrangement, as coupled through theconnectors 42 and 44 to the terminals 62 and 64, respectively, result ina 4-pole characteristic of the winding 40. The coil grouping and windingarrangement as coupled through the connectors 46 and 48 to the terminals66 and 68, respectively, result in a lO pole characteristic of thewinding 40.

Assuming for purposes of explanation that current at a selected instantis entering terminal 62, the current is split in connector 42 with oneportion going to the right into connector riser 70 and the other portionto the left into connector riser 72. The portion entering riser 70progresses into the winding portion at the bottom of slot 6, crossesover the top into the upper winding portion in the slot 50, andsuccessively into the respective bottom and top winding portions inslots 5 and 49 into the supplementary connector 50, thence successivelyslots 54, 38, 53, 37, connector 52, and slots 31, 47, 32 into descender74, through connector 48 into riser 76 and successively slots 60, 44,59, 43, connector 54, slots 25, 41, 26, 42, and descender 76 out theterminal 64 via connector 44.

The portion entering riser 72 passes successively through windingportions in slots 36, 20, 35, 19, connector 56, slots 24, 8, 23, 7,connector 58, slots 1, 17 2, 18, descender 78, connector 46, riser 80,slots 30, 14, 29,13, connector 60, slots 55, 11, 56, 12, and descender82 out the terminal 64 via the connector 44.

In the lO-pole mode instantaneous current entering terminal 66 splits inconnector 46 with one portion going to the left into riser (needescender) 78 and the other portion to the right into the riser (needescender) 80. The portion entering riser 78 traverses the windings inslots 18, 2, 17, l, connector 58, slots 7, 23, 8, 24, connector 56,slots 19, 35, 20, 36 into descender (nee riser) 72, connector 42, riser70, slots 6, 50, 5, 49, connector 50, slots 54, 38, 53, 37, connector52, slots 31, 47, 32, 48, descender 74 and out terminal 68 via connector48.

The portion entering riser 80 traverses the windings in slots 30, 14,29, 13, connector 60, slots 55, 11, 56, 12, descender 82, connector 44,riser (nee descender) 76, slots 42, 26, 41, 25, connector 54, slots 43,59, 44, 60, descender 76 and out the terminal 68 via connector 48.

The direction of the instantaneous current flow as assumed above in eachof the 4-pole and lO-pole configurations is depicted on FIG. 2 by arrowson the winding portions in the slots. The upper horizontal row 84 ofarrows is for the 4-pole configuration and the lower horizontal rowv 86of arrows is for the l0-pole configuration. From this it willbe seen inslots 1, 2, 7 and 8, for

6 example, that the current flow is in opposite directions as betweenthe 4-pole and lO-pole configuration, whereas in slots 37, 38, 49 and50, for example, the current flow direction is the same for eachconfiguration.

It is apparent, of course, that the voltage output of the winding shownin FIG. 2 will be different as between the terminals 62 and 64 whencoupled to the output as four poles and the terminals 44 and 46 whencoupled to the output as 10 poles. Thus for the same flux density, thevoltage output on 4 poles in a particular embodiment mentioned it wasdesired to provide the load with constant volts per Hertz since the loadwas a linear induction motor. In other words, 250 volts per phase wasthe design objective for the lO-pole configuration having an output of150 Hz, as against the desired 'volts per phase in the 60 Hz 4-poleconfiguration.

To this end a regular lO-pole winding was placed in the slots which weremade deeper as necessary to accommodate this additional winding. Thefinal winding connection was as shown in FIG. 3 in which the winding forone phase'is illustrated in detail.

Referring to this figure, the three-phase winding 100 is illustratedschematically as'comprising phase winding complexes 102, 104 and 106constituting the winding arrangements for phases A, B and C, forexample. Since all three phases are identical only phase A, for example,as exemplified by complex 102, need be explained in detail.

To this end the illustration for complexes 104 and 106 areof reducedproportions to permit the expanded illustration of complex 102 forclarity and ease of description. Winding complex 102 comprises a closedwinding 108, which may correspond to the winding 40 of FIG. 2, and awinding 110 which may be considered as a regular winding, adopted toprovide the additional generated voltage as referred to hereinabove.Assuming approximately the same flux densities, the half of the FIG. 2slots remote from the air gap would be filled with the regular winding110 while the remaining half of the slots would be filled with theclosed winding 108. Closed winding 108 comprises winding coils 112, 114,116 and 118 coupled together, as shown, to terminal points 120, 122, 124and 126. Terminal point 124 is common to one end each of windings 110,114 and 116. Terminals and 126 are coupled to switch 128 for selectiveconnection to the output terminal 130 of phase A from the complex 102. Aterminal 132 at the distal end of the winding 110 and the terminal 122are coupled to switch 134 for selective connection to the terminal point136 which is common to the coupling of winding complexes 102, 104 and106 in wye-connection fashion. Winding complexes 104 and 106 havesimilar switching arrangements as shown, but not described in detail,for selective coupling to the common wye terminal 136 and to therespective output terminal points 138 and 140 for phases B and C.

The switches 128 and 134 for winding complex 102, as well as theswitches for the winding complexes 104 and 106, are arranged foractuation by a field coil 142. The switches 128 and 134 may have anormal switching mode, when the coil 142 is not energized, to couple thephase A terminal 130 to the winding terminal point 126 and the commonwye terminal 136 to the winding terminal point 122, as shown in FIG. 3.

Assuming instant current flow direction to be from the phase A terminalpoint 130 towards the common terminal point 136, it is seen that thecurrent splits at terminal 126 to enter windings 116 and 118. Thecurrent portion in winding 116 traverses terminal point 124 into winding114 and thence to terminal point 122. The current portion in winding 118traverses terminal point 120 into winding 1 12 and thence to join theother portion at terminal point 122, whereafter it traverses the switch134 to the common terminal point 136.

When the field coil 142 is energized, the switches 128 and 134 operateto couple the phase A terminal point 130 to the winding terminal point120 and the common wye terminal point to the winding terminal point 132.Thus with instant current flow as aforesaid, from the phase A terminalpoint 130 towards the common terminal point 136, the current splits atterminal 120 to enter windings 112 and 118. The portion of current inwinding 112 flows from terminal 122 and through winding 114 to terminal124. The current portion in winding 1 l8 traverses terminal 126 andthrough winding 116 to join the other portion at terminal 124 whereafterthe total current flows through winding 110 and traverses terminal 132and switch 134 to the common terminal point 136. It will be observedthat current flow in either switching mode flows in the same directionin windings 112 and 116 but in opposite directions in windings 114 and118. The similarity of the closed winding 108 of FIG. 3 to the winding40 of FIG. 2 is now obvious. Thus, the terminal points 122 and 126 ofFIG. 3 are the counterpart of the respective terminal points 62 and 64of FIG. 2, whilst the terminal points 120 and 124 are the counterpart ofthe respective terminal points 66 and 68 of FIG. 2.

That is to say, with a winding configuration such as that of FIG. 2,current flow into terminal 126, to split with portions going throughwindings 116, 118 and 114, 112 to terminal 122, provides a 4-poledynamoelectric structure. Similarly, current flow into terminal 120, tosplit with portions traversing windings 112, 1 18 and 114, 116 toterminal 124, provides a lO-pole machine which has a regular winding 110to provide the desirably additional voltage for the 150 Hertzconfiguration.

What I claim is:

l. Dynamoelectric apparatus comprising:

a. rotor and stator members;

b. magnetic excitation means on each of said rotor and stator membersfor operating said rotor at a predetermined synchronous speed inresponse to the application of single phase alternating current power toone of said magnetic excitation means; and

c. an alternating current output winding means comprising anelectrically closed loop coil disposed on said stator member andarranged to provide multiphase alternating current of at least twofrequencies at two pairs of output terminals connected to said closedloop coil at four different locations thereon so as to define twoelectrically different pole arrangements of said output winding means.

2. The apparatus of claim 1 in which the output at one pair of saidterminals is that of a 4-pole arrangement of said output winding meansand the output at another pair of said terminals is that of a l-polearrangement of said output winding.

3. The apparatus of claim 1 in which the output at one pair of saidterminals is that of a 2-pole arrangement of said output winding meansand the output at another pair of said terminals is that of a 6-polearrangement of said output winding.

4. The apparatus of claim 1 in which said magnetic excitation means onsaid rotor provides two sets of 5 magnetic excitation poles,

one of said pole sets differing in number of magnetic excitation polesfrom the other.

5. The apparatus of claim 4 in which one of said sets of magneticexcitation poles comprises a magnetic 10 4-pole set and the other amagnetic l0-pole set.

6. The apparatus of claim 4 in which one of said sets of magneticexcitation poles comprises a magnetic 2-pole set and the other amagnetic 6-pole set.

7. Dynamoelectric apparatus comprising:

a. relatively movable dynamoelectric members;

b. a first winding arrangement on one of said members, arranged for thesupply thereto of alternating current power of a first number of phases;

c. a second winding arrangement on said one of said members, arrangedfor the output therefrom of alternating current power of a second numberof phases different from said first number of phases; said secondwinding arrangement having first and second frequency output windingterminal points;

d. terminal means coupled to said terminal points of said second windingarrangement and arranged to selectively supply two frequencies ofalternating current power therefrom to a load coupled to said terminalmeans; and

e. first and second magnetic excitation means on the other of saiddynamoelectric members, one of said excitation means providing adiffering number of magnetic poles from the other and one of saidexcitation means being arranged to cooperate with said first windingarrangement to operate said dy'-.

namoelectric members at a predetermined synchronous speed.

8. Dynamoelectric apparatus comprising:

a. relatively movable dynamoelectric members;

b. magnetic excitation means on one of said members;

c. a first winding arrangement on one of said members, arranged for thesupply thereto of alternating current power of a first number of phases,said first winding arrangement being in magnetic coupling relation tosaid magnetic excitation means to drive said dynamoelectric membersrelative to each other;

(I. a second winding arrangement on one of said members, said secondwinding arrangement comprising an electrically closed loop coilmagnetically coupled to said magnetic excitation means arranged for theoutput therefrom of alternating current power of a second number ofphases different from said first number of phases in response torelative movement between said members;

e. terminal means coupled to said electrically closed loop coil of saidsecond winding arrangement said terminal means defining two differentmulti-pole configurations of said second winding arrangement toselectively supply two frequencies of alternating current powertherefrom to a load coupled to said terminal means.

9. The apparatus of claim 8 in which said terminal means includes fourterminal elements, two of said elements arranged to supply alternatingcurrent power arranged to supply alternating current of anotherfrequency.

10. The apparatus of claim 8 in which said excitation means comprisesfirst and second excitation means, said first means providing adiffering number of magnetic poles from that provided by said secondmeans.

11. A dynamoelectric machine comprising:

a stator including a single phase primary winding disposed on saidstator and defining a plurality of primary stator poles to provide achanging magnetic field in response to the application of single phasealternating current, said stator further including multiphase secondarywinding means connected to a plurality of output terminal;

a rotor including exciting winding means defining each of a firstplurality of rotor poles greater in number than said first plurality ofrotor poles; and,

means for selectively supplying exciting current to said excitingwinding means to excite said first plurality of rotor poles to operatesaid rotor at a synchronous speed defined by the number of saidplurality of primary stator poles and the frequency of said alternatingcurrent, and to selectively excite said second plurality of rotor poles,

said multiphase secondary winding means being magnetically coupled tosaid exciting winding means to produce, at said output terminals, amultiphase output voltage having a first frequency in response to theexcitation of said first plurality of rotor poles and having a secondfrequency higher than said first frequency in response to the excitationof said second plurality of rotor poles.

12. The dynamoelectric machine of claim 11 wherein said multiphasesecondary winding means includes a first winding connected between firstand second of said plurality of output terminals and a second windingconnected between third and fourth of said plurality of outputterminals, said first winding having a first magnetic polecharacteristic and said second winding hav- 10 ing a second magenticpole characteristic differing from said first magnetic polecharacteristic.

13. The dynamoelectric machine of claiam 12 wherein said first magneticpole characteristic is that of a 4-pole set and wherein said secondmagnetic pole characteristic is that of a lO-pole set.

14. The dynamoelectric machine of claim 12 wherein said first magneticpole characteristic is that of a 2-pole set and wherein said secondmagnetic pole characteristic is that of a 6-pole set.

15. The dynamoelectric machine of claim 11 further including:

a drive motor operable in response to multiphase alternating current atspeeds related to the frequency of the alternating current;

switching means connected between said output terminals and said drivemotor for selectively applying said multiphase output voltage of saidfirst frequency and of said second frequency from said multiphasesecondary winding means to said drive motor.

16. The dynamoelectric machine of claim 12 further including:

a drive motor operable in response to multiphase alternating current atspeed related to the frequency of the alternating current;

switching means connected between said output terminals and said drivemotor for selectively applying said multiphase output voltage of saidfirst frequency and of said second frequency from said multiphasesecondary winding means to said drive motor.

17. The apparatus of claim 11 in which one of said first and secondplurality of rotor poles comprises a magnetic 4-pole set and the other amagnetic l0-pole set.

18. The apparatus of claim 12 in which one of said first and secondplurality of rotor poles comprises a magnetic 2-pole set and the other amagnetic 6-pole set.

1. Dynamoelectric apparatus comprising: a. rotor and stator members; b.magnetic excitation means on each of said rotor and stator members foroperating said rotor at a predetermined synchronous speed in response tothe application of single phase alternating current power to one of saidmagnetic excitation means; and c. an alternating current output windingmeans comprising an electrically closed loop coil disposed on saidstator member and arranged to provide multi-phase alternating current ofat least two frequencies at two pairs of output terminals connected tosaid closed loop coil at four different locations thereon so as todefine two electrically different pole arrangements of said outputwinding means.
 2. The apparatus of claim 1 in which the output at onepair of said terminals is that of a 4-pole arrangement of said outputwinding means and the output at another pair of said terminals is thatof a 10-pole arrangement of said output winding.
 3. The apparatus ofclaim 1 in which the output at one pair of said terminals is that of a2-pole arrangement of said output winding means and the output atanother pair of said terminals is that of a 6-pole arrangement of saidoutput winding.
 4. The apparatus of claim 1 in which said magneticexcitation means on said rotor provides two sets of magnetic excitationpoles, one of said pole sets differing in number of magnetic excitationpoles from the other.
 5. The apparatus of claim 4 in which one of saidsets of magnetic excitation poles comprises a magnetic 4-pole set andthe other a magnetic 10-pole set.
 6. The apparatus of claim 4 in whichone of said sets of magnetic excitation poles comprises a magnetic2-pole set and the other a magnetic 6-pole set.
 7. Dynamoelectricapparatus comprising: a. relatively movable dynamoelectric members; b. afirst winding arrangement on one of said members, arranged for thesupply thereto of alternating current power of a first number of phases;c. a second winding arrangement on said one of said members, arrangedfor the output therefrom of alternating current power of a second numberof phases different from said first number of phases; said secondwinding arrangement having first and second frequency output windingterminal points; d. terminal means coupled to said terminal points ofsaid second winding arrangement and arranged to selectively supply twofrequencies of alternating current power therefrom to a load coupled tosaid terminal means; and e. first and second magnetic excitation meanson the other of said dynamoelectric members, one of said excitationmeans providing a differing number of magnetic poles from the other andone of said excitation means being arranged to cooperate with said firstwinding arrangement to operate said dynamoelectric members at apredetermined synchronous speed.
 8. Dynamoelectric apparatus comprising:a. relatively movable dynamoelectric members; b. magnetic excitationmeans on one of said members; c. a first winding arrangement on one ofsaid members, arranged for the supply thereto of alternating currentpower of a first number of phases, said first winding arrangement beingin magnetic coupling relation to said magnetic excitation means to drivesaid dynamoelectric members relative to each other; d. a second windingarrangement on one of said memBers, said second winding arrangementcomprising an electrically closed loop coil magnetically coupled to saidmagnetic excitation means arranged for the output therefrom ofalternating current power of a second number of phases different fromsaid first number of phases in response to relative movement betweensaid members; e. terminal means coupled to said electrically closed loopcoil of said second winding arrangement said terminal means defining twodifferent multi-pole configurations of said second winding arrangementto selectively supply two frequencies of alternating current powertherefrom to a load coupled to said terminal means.
 9. The apparatus ofclaim 8 in which said terminal means includes four terminal elements,two of said elements arranged to supply alternating current power of onefrequency and the other two of said elements arranged to supplyalternating current of another frequency.
 10. The apparatus of claim 8in which said excitation means comprises first and second excitationmeans, said first means providing a differing number of magnetic polesfrom that provided by said second means.
 11. A dynamoelectric machinecomprising: a stator including a single phase primary winding disposedon said stator and defining a plurality of primary stator poles toprovide a changing magnetic field in response to the application ofsingle phase alternating current, said stator further includingmultiphase secondary winding means connected to a plurality of outputterminal; a rotor including exciting winding means defining each of afirst plurality of rotor poles greater in number than said firstplurality of rotor poles; and, means for selectively supplying excitingcurrent to said exciting winding means to excite said first plurality ofrotor poles to operate said rotor at a synchronous speed defined by thenumber of said plurality of primary stator poles and the frequency ofsaid alternating current, and to selectively excite said secondplurality of rotor poles, said multiphase secondary winding means beingmagnetically coupled to said exciting winding means to produce, at saidoutput terminals, a multiphase output voltage having a first frequencyin response to the excitation of said first plurality of rotor poles andhaving a second frequency higher than said first frequency in responseto the excitation of said second plurality of rotor poles.
 12. Thedynamoelectric machine of claim 11 wherein said multiphase secondarywinding means includes a first winding connected between first andsecond of said plurality of output terminals and a second windingconnected between third and fourth of said plurality of outputterminals, said first winding having a first magnetic polecharacteristic and said second winding having a second magentic polecharacteristic differing from said first magnetic pole characteristic.13. The dynamoelectric machine of claiam 12 wherein said first magneticpole characteristic is that of a 4-pole set and wherein said secondmagnetic pole characteristic is that of a 10-pole set.
 14. Thedynamoelectric machine of claim 12 wherein said first magnetic polecharacteristic is that of a 2-pole set and wherein said second magneticpole characteristic is that of a 6-pole set.
 15. The dynamoelectricmachine of claim 11 further including: a drive motor operable inresponse to multiphase alternating current at speeds related to thefrequency of the alternating current; switching means connected betweensaid output terminals and said drive motor for selectively applying saidmultiphase output voltage of said first frequency and of said secondfrequency from said multiphase secondary winding means to said drivemotor.
 16. The dynamoelectric machine of claim 12 further including: adrive motor operable in response to multiphase alternating current atspeed related to the frequency of the alternating current; switchingmeans connected between said output terMinals and said drive motor forselectively applying said multiphase output voltage of said firstfrequency and of said second frequency from said multiphase secondarywinding means to said drive motor.
 17. The apparatus of claim 11 inwhich one of said first and second plurality of rotor poles comprises amagnetic 4-pole set and the other a magnetic 10-pole set.
 18. Theapparatus of claim 12 in which one of said first and second plurality ofrotor poles comprises a magnetic 2-pole set and the other a magnetic6-pole set.